Sorry i certainly a stupid question but i like to make sure i do thing in the right way.
I have some component in a breadboard that use a lot of power ( more than what my arduino can provide ). So i have an external power connected to the breadboard. The Atmega is still on the arduino board and i am using digital pin to communicate with the component on the breadboard. Do i need to connect the GND pin of my arduino to the GND on the breadboard ? ( which is connected to an external power) . I am doing that right now because i thought it was correct ( not sure) but i like to know the why.
Thanks in advance
All the best